The summer flowering annual Amaranthus has been cultivated for over 8000 years , used as a grain plant by The Aztecs and in southern China as leaf vegetable.
In her book Oriental Vegetables, Joy Larkcom lists some ten edible species and includes interesting recipes for Spicy Amaranthus where it is stir fried with lots of different spices as well as one where it is cooked with Lentils and Chick Peas and served with roasted pork.Yum!
In Mandarin, Amaranthus is called Xian cai and in Japanese Hiyuna.
Apart from the edible species, there are also some splendid decorative ornamentals in this group as well including the amazing A.salicifolius 'Flaming Fountain' and the brilliant leaf colour of A. tricolor perfecta 'Josephs Coat' .Most grow to at least a metre in height and will self seed and return the following year given favourable conditions. I like the "dreadlocks" of A caudatus below.
This makes a lovely splash of lime green colour in an ornamental vegetable garden. The seed is sold in packets at Asian food stores but it will self seed and return each year.
Amaranthus caudatus 'Viridis'
Amaranthus salicifolious Flaming Fountain